ESRL Global Systems Division

Revolutionary Air Profiling System Parachuted from Balloon at 72,000 ft

A team of NOAA/ ESRL scientists from the Global
Monitoring Division (GMD) and the Global Systems Division (GSD)
recently completed the third successful stratospheric balloon flight,
testing the AirCore™ atmospheric gas concentration profile
sampler. The AirCore™ consists of a 250 ft. thin-walled,
stainless steel coil of tubing that is open and subsequently fills
with air as the coil is parachuted to the ground. During the descent,
a so called "noodle of air" flows into the tube and maintains a record
of gas concentrations at various altitudes. The air is analyzed by
pushing it out of the tube into an analyzer with a "push" gas.
"Because of its simple design, operation, and low cost, the
AirCore™ is a breakthrough in atmospheric gas concentration
profiling," says Pieter Tans, group leader of the ESRL Carbon Cycle
and Greenhouse Gas group.

Atmospheric profiling of trace gases is presently
accomplished by flying an aircraft with in situ samplers or collecting
bottles of air during aircraft profiles. Both methods are expensive
and provide limited altitude information as most sampling aircraft
cannot fly above 30,000 ft. The Aircore™ weighs only 16 pounds
and can be carried aloft with inexpensive meteorological balloons
conducting up to 25 profiles with essentially expendable equipment for
the price of one high-altitude aircraft sampling flight.

This latest balloon flight was conducted jointly by
ESRL and the Edge of Space Science (EOSS) Balloon Group, a Colorado
educational non-profit corporation for promoting science and education
through amateur radio and high-altitude balloon flights. The balloon was
launched and
cut down by radio command from the EOSS ground station at Windsor,
CO. with the payload landing some 30 miles away entangled in a power
line. The AirCore™ was recovered and returned the same day for
trace gas analyses at ESRL laboratories in Boulder.

The initial analyses show that CO2 is not uniformly
distributed through the atmosphere, as has generally been believed.
Figure 1 shows the profile of CO2 distribution with altitude
plotted with temperature. Note in Figure 2, showing the CO2
and relative humidity profiles, that AirCore™ worked well even
as it descended through a cloud (between 8 and 10 km).

Fig. 1: AirCore™ profile of CO2
and air temperature.

Fig. 2: AirCore™ profile of CO2
and relative humidity.

ESRL has submitted a patent application for the
AirCore™ because of its enormous potential to obtain numerous
profiles of trace gases on a global scale. The AirCore™ could
feasibly collect 1000 or more profiles inexpensively on a daily basis
around the world as it can be easily deployed on commercial and
private aircraft, from Unmanned Aircraft System platforms, or carried
aloft with small balloons. The AirCore™ team on the just
completed flight consisted of Pieter Tans, Aaron Watson, and Colm
Sweeney of GMD, and Russell Chadwick and Randy Collander of GSD.